Thus, the present study compared these mutations of colorectal NECs with those of colorectal ACs after tumour site matching and detected no significant differences in the frequencies of TP53, KRAS, APC, PIK3CA, PTEN, GNAS, and SMAD4 mutations between 30 NEC tumours and 100 AC tumours. The gene discussed is PTEN; the disease is neuroendocrine carcinoma.